www.hvactechgroup.com - forums

HVAC Forums => HVAC Help => Topic started by: wazlife on October 20, 2013, 04:34:31 PM

Title: Transformer troubleshooting
Post by: wazlife on October 20, 2013, 04:34:31 PM
I have 120VAC at L1 & L2 on the control board. At SEC-1 and SEC-2 (where 24VAC should be present) there is a reading of zero. Transformer is done, correct?

Title: Re: Question
Post by: walker on October 20, 2013, 04:51:44 PM
Check the transformer to see if you have 24v there.
Title: Re: Question
Post by: Admin on October 20, 2013, 05:38:42 PM
Have you verified there is 120V feeding the primary side of the transformer?  What kind of furnace are you working on and is it possible your line voltage should be connected to the L1 and N terminals for 120V?

Once the transformer has been disconnected use the audible resistance setting on your meter.  When you measure across either the 2 primary wires (120V) or 2 secondary wires (24V), connected to the transformer, the meter should beep.  The side that doesn't beep will let us know if our transformer has a primary or secondary side short.

Title: Re: Transformer troubleshooting
Post by: wazlife on October 21, 2013, 05:55:31 PM
It was the transformer.

There wasn't 24V on the secondary side when I was back to fix it. Put in the new transformer and voila! working furnace.